Triangular plane girder for aeroplanes



Nov, 29, 1932.. c, RQSA'TELLHI 1 889394 TRIANGULAR PLANE GIRDER FOR AEROPLANES Filed Dec. 11, 1950 Patented Nov. 29, 1932 UNITED STATES PATENT oFFIcE CELESTINO ROSATELLI, or roam, ITALY, ASSIGNOR TO FIAT SOGIETA ANOLN'IMA, 0F

TURIN,

ITALY Application filed December 11, 1930, Serial No. 501,711, and. in Italy September 23, 1930.

10 the braced girder which is in'accordance with the known statical graphical law expressed by the formula wherein X is the number of members and Y the number of knots of the girder.

As it is well known the above mentioned formula expresses the necessary and sufficient condition enabling a braced girder to be statically determined and undeformable.

The accompanying drawing shows diagrammatically by way of example a girder construction for an aeroplane fuselage, in which the apertures for the entrance doors are formed without the necessity of employing special means for reinforcing the girder and without effecting the stability of said girder.

Figure 1 shows diagrammatically a part of the girder forming the side wall of the fuselage.

Figure 2 is a general view of an aeroplane, of which the fuselage is constructed with the girder shown in Fig. 1.

Referring to the drawing: A and A denote the two fully free large pentagonal apertures in correspondence with which the doors .9 and s, (Fig. 2) shall be fitted. The apertures A and A divide the girder into three sections; considering'in such section thepartsBGFED,EGHILMand M N O P Q and referring to the members as a and to the connections as 9bit will be found that a=33 and n 18 The said values fulfill the necessary and suflicient condition for obtaining a statically determined and undeformable girder. In fact 33=2 18-3 Of course the above described system may be applied in cases other than that mentioned above without departing from the spirit of this invention.

What I claim is: a

In an aircraft body having lateral openings for the doors extending a substantial portion of the height of the body, a longi tudinal truss at a side of the body and having openings corresponding with the body openings, said truss comprising upper and lower beams extending continuously throughout the portion of the body in which said door openings are located, uprights connecting said beams between said openings, a horizontal member for connecting intermediate points of said uprights, diagonal struts between said uprights converging towards the connecting point of this horizontal member with one of said uprights, and struts between the connecting points of said horizontal member and the lower beam.

In testimony that I claim the foregoing as my invention, I have signed my name.

CELESTINO ROSATELLI. 

